T.V. siganls are the same as Radio signals, this means if you have any items between your antenna and the signal source there is probably going to be some signal loss.
Therefore you should try and make sure you have a clear line of site from your antenna to the signal source you are using.

Which antenna is best for you?
Improved reception can be obtained only by using a good antenna. There are many types, each designed for a specific purpose, and each with certain limitations. This section may help you choose the best antenna for your needs, or find out whether your present antenna is adequate.

Indoor Antennas
The most common indoor antenna for VHF reception (channels 2 - 13) is the Rabbit ears type. UHF reception (channels 14 - 83) is obtained with a loop or bow tie antenna. Generally, these antennas are satisfactory only within about 13 km of the transmitting tower, and often less if the signal is blocked by buildings or other obstructions.
If you have one of these antennas, try it in various positions to see which brings in the best picture.
Each time you change channels, you may have to change the position of the antenna. Also, pull the rabbit ears all the way out for the lowest channel (2) and push them in for the higher channels. If the picture remains poor for all antenna positions, there is a good chance that you need an outdoor antenna.

Outdoor Antennas
Outdoor antennas are larger and more efficient than indoor types. Generally, the higher the antenna and the greater the number of elements (metal rods) to capture the signal, the more efficient it will be. The choice of an outdoor antenna depends on your location and what you want it to do.
Combination UHF-VHF antennas that are in one straight line are no good!

Pointing your antenna
It is surprising how many antennas are installed pointing in the wrong direction - usually backwards. A poorly aimed antenna may still pull in a usable signal but it will be comparatively weak. Even if the antenna was installed correctly, wind can sometimes turn it slightly away from the direction in which it was originally aimed.
Apply the following general rules for positioning antennas:
* aim the shorter elements toward the station tower;
* when V-shaped elements are uses, point the open end of the V toward the station tower;
* experiment by pointing the antenna in various directions and checking the picture. In some cases, you may find that the best signal is obtained when the antenna points slightly away from the station, because of obstacles in the path of the signal.

Are your antenna and lead-in wire properly installed?
Problems with TV reception can be traced to improperly installed antennas and lead-in wires.
* The Antenna
If you wish to install a new antenna or check whether your present antenna is properly installed you may wish to consult a TV antenna installer who is familiar with installation conditions. Normally outdoor television antennas are mounted on a post or tower. These structures should be attached to a ground rod using copper wire of at least No. 12 gauge.
* The Lead-in Wire
It is important to use a good lead-in wire to connect the antenna to your TV set. Most installations use the ribbon, or twin-lead type that has two wires. A shielded-type coaxial cable may be necessary in some situations to minimize interference.

Do's and don'ts for installation
* For the usual twin-lead wire, standoff insulators must be used to hold the wire away from the mast, roof, walls and metal ducts on its way down to the TV set. There should be no direct contact between the lead-in wire and any metal surfaces, except at the terminals.
* The first standoff insulator should be as close to the antenna terminal as possible. * The twin-lead wire should be twisted one turn for every three feet of length to help prevent excessive movement in the wind and to minimize interference. Don't twist too tightly or the wire may break.
* Never paint the lead-in, terminals, standoff insulators or lightning arrestor. * Do not use a combination of twin-lead and coaxial cable without the proper matching transformers.
* Do not splice the lead-in wire, even with solder. Splices decrease the amount of signal reaching the TV set and reduce quality.
* Do not let excess wire coil behind the TV set. This may create ghosting in the picture or signal loss. Cut off any excess wire when the installation is complete.
* Attach both lead-in wires securely to the two antenna input terminals.
* To keep the two wires from touching each other, attach each wire to a U-shaped metal clip, which fits neatly under the terminal screw.
* There may be two pairs of these terminals (connectors), one labelled VHF and the other UHF. Antennas for channels 2 - 13 should be connected to the VHF terminals and antennas for channels 14 - 83 should be connected to the UHF terminals. Only one antenna should be connected at a time. If an exterior antenna is connected, the rabit ears should be disconnected.

Poor reception areas
If you live in an area where reception is poor, you may wish to consider installing a preamplifier, a small inexpensive device that can be mounted on the antenna. Be sure to buy a model that matches the type of lead-in wire you are using.
These amplifiers boost the incoming signal and may provide a very significant increase in pisture quality.

Nothing lasts forever
Corrosion will reduce the effectiveness of TV antennas. This is a particularly serious problem along the sea coast, where the air contains a lot of salty moisture, or in urban areas near major industries. Over time, aluminum antennas develop a coat of aluminum oxide, preventing some of the signal from reaching your TV set. Deformed or broken elements can also reduce the antenna's efficiency.
Corroded or bent antennas should be replaced. Good quality antennas can now withstand the effects of rain, snow and corrosion for many years. Lead-in wires can become dry or brittle with age and the two wires inside may short-circuit. If this occurs, the wire should be replaced.

Isolating your television interference problem
The following checklist is intended to help you decide if your television reception problem is due to an interfering signal or equipment problems in your antenna system.
1. A visual check of the antenna should determine if:
* The antenna is the correct type.
* It is positioned to prevent screening by buildings, trees or other aerials.
* It points to the desired station.
* It is free from corrosion, wind damage or loose connections.
2. A check of the lead-in should determine if:
* It is a low signal-loss type.
* It is in good condition (free of corrosion and water penetration).
* The terminals or soldered connections are in good condition.
* A pre-amplifier (if used) is working satisfactorily and is the correct type for the channel in use.

IDENTIFYING TELEVISION INTERFERENCE

Interefernce with your Television signal can come from many sources. Most of these interference problems can be traced to one or more of the following factors:
1. Characteristics of the receiving system, for example, television receiver or antenna systems design and installation.
2. Environment of the receiving system, for example, distance from television transmitter and intervening terrain or presence of nearby radio transmitter.
3. Characteristics of radio frequency generating devices such as CB of VHF communication radio transmitters.
4. Practices of radio transmitter operators, for example, operating an illegal overpowered transmitter or amplifier.
5. Condition of the receiving system such as a faulty TV receiver in need of repair.
The control of some of these factors is within the jurisdiction of Industry Canada. There are technical standards and regulations concerning the way in which radio transmitters are operated. However this equipment may be properly operated and it is still possible for you to experience interference.
** Radio Transmitter Interference
This problem will normally affect VHF channels only. You will notice a pattern of horizontal lines over the picture that changes or moves as the radio transmitter operator talks.
** Electrical Appliance Interference
This problem can affect any channel. You will notice white sparkles in the picture and you may hear a sizzling or buzzing noise in the sound. This problem will come and go depending on the operation of the appliance. When the problem appears, try to track down the offending appliance in your home. Do not confuse this problem with a weak signal where the picture may be weak but the sound quality will not usually be affected.
** FM Interference
Interference from a nearby FM Broadcast station could cause a varying pattern in the picture which will change with the sound of the FM station and not the sound of the TV program. Although it normally will affect TV channel 6 only, other channels in the VHF band (2 - 13) may occasionally be affected. If the pattern varies with the sound of the TV program then the problem is likely the fine-tuning of the TV. Re-adjust your fine tuning control to eliminate the problem.
** Co-channel Interference
This problem will occur when your TV set is receiving two signals from stations on the same channel. One picture will be stronger than the other with the weak signal showing in the background. Co-channel Interference is due to either atmospheric conditions or the location of your home in relation to the TV stations. While little can be done to correct a problem caused by atmospheric conditions, it is usually temporary. However, if it is caused by the location of your home in relation to the TV stations, use of a directional antenna may help to eliminate the problem.
** Ghosting
This TV signal problem can be caused by signal reflections from a mountain, building or other structure, so that two signals are sent over different paths to your TV set and arrive at slightly different times. Wtih ghosting you will note that the two images are the same. Rotation of your TV antenna to a new position or installation of a coaxial cable lead-in wire may resolve this problem.
** Electrical Interference from Power Lines
This type of interference will produce bars across your picture a If this occurs on your TV picture you should contact your power utility.